Glycolysis Flashcards
What is the main focus of glycolysis
To generate energy from glucose
What is glycolysis
A sequence of reactions where gluscose from digestion is converted to two molecules of pyruvate
C6h12o6 to c3h3o3
What are the two stages of glycolysis
Trapping and preparation
Oxidation to pyruvate
What is the goal of the trapping and preparation step of glycolysis
Trap glucose in the cell and transform it into fructose 1,6 bisphosphate (something that can be better broken down)
What do the kinases in glycolysis do
Hydrolyze atp to adp to add a phosphate group to the molecule
What are the kinases that are used in the trapping and preparation step
First to make glucose 6 phosphate (Hexokinase)
Then to make fructose 1 6 biphosphate (phosphofructokinase)
What does Hexokinase do in terms of water
It removes water from its active site so that the reaction of atp with water to make adp doesn’t happen
I does this by having an induced fit
Want phosphorylated glucose, if water reacts then the atp won’t be used properly
What happens to make glucose stay in the cell for glycolysis to occur
It gets phosphorylates by Hexokinase and becomes more charged and polar
What does phosphoglucose isomerase do
Converted the hard to break down glucose 6 phosphate (more stable)
to the easier 5 membered fructose 6 phosphate (less stable)
Aldose to ketose
This is reversible
What happens to the fructose 6 phosphate
It’s gets phosphorylated to fructose 1,6 biohospahte
This is irreversible step and traps the fructose in this form so it can then be broken down
Is glucose to glucose 6 phosphate reversible
No
What happens to the F 16 biphosphates after it is made
Aldolase enzyme turns it into the 3 carbon Glyceraldehyde 3 phosphate which is used for stage 2 of glycolysis
What is the isomer problem of Glyceraldehyde 3 phosphate
What converts the isomers
We need the Glyceraldehyde 3 phosphate form but equilibrium favours the dihydroxyacetone version
The thing that converts the isomers is triose phosphate isomerase
In the first stage of glycolysis how much atp is formed and made
Atp is hydrolyzed twice to make two adp
So far no atp is MADE
How many steps in glycolysis
10 steps
5 steps in parts 1 and 2
What happens at the beginning of stage two of glycolysis
Glyceraldehyde 3 phosphate dehydrogenase reducers NAD to NADH
Oxidized inorganic phosphate
This turns Glyceraldehyde 3 phosphate to 1,3 bi phosphoglycersate through oxidation
How many times does stage two in glycolysis happen
2 times out of
What are the high energy compounds used to make atp from adp
1,3 BPG
Phosphoenol pyruvate
Creatine phosphate
What are the low energy compounds that use atp to get phosphorylate and turn its into adp
Glucose 6 phosphate and glycerol 3 phosphate
The more negative delta g of a reaction,
The more favourable the reaction
More likely it’ll proceed
How much atp is made in the second stage of glycolysis
How much NADH
For 1 round 2 atp is made and 1 NADH
This step happens twice so 4 atp made and 2 NADH in total
Where does glycolysis happen
In the cytoplasm
Which has a higher absorbance, NAD+ or NADH
NAD+
The step to make 1,3 biphosphogycelrate in stage 2 of glycolysis has what type of intermediate
Why
A thio ester intermediate that’s linked to an enzyme
This lowers the energy barrier to go from being glycerldhyde three phosphate oxidized to the 1,3 BPG .
What is the delta g of the oxidation step in stage two glycolysis (to make 3 phosphoglycerate the oxidized version of Glyceraldehyde 3 phosphate
-50kJ/mo
A very favourable reaction
How is the oxidized Glyceraldehyde three phosphate (3 phophoglycerate) turned into 1,3 BPG via the intermediate
Through covalent catalysis of an enzyme with the Thio ester intermediate
Once the 1,3 biphosphoglycarate is made, how does it turn into 3 phosphoglycerate
Through the enzyme phosphoglycerate kinase, it does substrate level phosphorylation to turn adp to atp
After 3 phosphoglycerate is made what turns it into 2 phsophoglycerste
Phosphoglycerate mutase
Moving the phosphate from c 3 to c2
After 2 phosphoglycerate is formed what turns it into phosphoenol pyruvate
What type of reaction does it do
Enolase
It does a dehydration reaction and makes water leave
What is special about phosphoenol pyruvate
It’s a higher energy molecule meaning it’s has more potential to move a phosphoryl group from itself to adp
It’s less stable than an alcohol
What happened after phosphoenol pyruvate is formed
How is it an internal oxidation reduction
Pyruvate kinase help with substrate level phosphorylation and turns adp to atp
The resulting c3 of pyruvate is more reduced (more H) and the c2 is more oxidized
What is the seventh class of enzymes
Translocases
What is the over all net atp gain of glycolysis
What out Nadh gain
2 atp gained
2 NADH gained
